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Wednesday, 17 August 2011

In the world of solar energy, organic photovoltaic solar cells have a wide range of potential applications, but they are still considered an upstart. While these carbon-based cells, which use organic polymers or small molecules as semiconductors, are much thinner and less expensive to produce than conventional solar cells made with inorganic silicon wafers, they still lag behind in their ability to efficiently convert sunlight into electricity.

Now, UCLA researchers and their colleagues from China and Japan have shown that by incorporating gold nanoparticles into these organic photovoltaics — taking advantage of the plasmonic effect, by which metal helps to enhance the absorption of sunlight — they can significantly improve the cells' power conversion.

In a paper recently published in ACS Nano, the team of researchers, led by Yang Yang, a professor of materials science and engineering at the UCLA Henry Samueli School of Engineering and Applied Science and director of the Nano Renewable Energy Center at UCLA's California NanoSystems Institute, demonstrate how they sandwiched a layer of gold nanoparticles between two light-absorbing subcells in a tandem polymer solar cell in order to harvest a greater fraction of the solar spectrum.

They found that by employing the interconnecting gold-nanoparticle layer, they were able to enhance power conversion by as much as 20 percent. The gold nanoparticles create a strong electromagnetic field inside the thin organic photovoltaic layers by a plasmonic effect, which concentrates light so that much more of it can be absorbed by the subcells.To read more click here...